cellular respiration in germinating peas experiment

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Measuring Respiration of Germinating and Non-germinating Peas

Measuring Respiration of Germinating and Non-germinating Peas By: Krunal Patel

Introduction

          Living cells require transfusions of energy from outside sources to perform their many tasks – for example, assembling polymers, pumping substances across membranes, moving, and reproducing (Campbell, and Reece 162). Heterotrophs obtains its energy for its cells by eating plants that makes it own food (Autotrophs); some animals feed on other organisms that eat plants. The most beneficial catabolic pathway in an organism is cellular respiration, in which oxygen and glucose are consumed and where carbon and water become the waste products. The purpose of cellular respiration is to convert glucose into ATP(energy) for the organism. Respiration consists of glycolysis, the Krebs Cycle, and the oxidative  phosphorylation. Glycolysis, which occurs in the cytosol, breaks the six carbon glucose molecule into two pyruvates. During this stage two ATP and two NADH molecules are made. The next step in respiration is the Krebs cycle. The Krebs cycle uses the two pyruvates made during glycolysis and converts them to Acetyl-CoA and carbon dioxide to make three NADH, one FADH 2 ,  and two CO 2 through redox reactions, and goes to the Electron Transport Chain. ATP is also formed during the Krebs cycle (Campbell, and Reece 166). Since two pyruvates are made during glycolysis, the Krebs cycle repeats two times to produce four CO 2 , six NADH, two FADH 2 , and two ATP (Campbell, and Reese 166). The last stage in cellular respiration is the Oxidative phosphorylation Electron Transport. The Oxidative phosphorylation occurs in the inner membrane of the mitochondria. The electron transport chain is powered by electrons from electron carrier molecules NADH and FADH 2 (Campbell, and Reese 166). As the electrons flow through the electron chain, the loss of energy by the electrons is used to power the pumping of electrons across the inner membrane. At the end of the electron transport chain, the electrons from the inner membrane bind to two flowing hydrogen ions to form water molecules. The protons, outside the inner membrane, flow down the ATP gradient and make a total of thirty two ATP (Campbell, and Reese 166).

In this experiment, an apparatus called a respirometer is used. A respirometer is a tool used to observe exactly how much oxygen was consumed by the peas and the glass beads. Since the carbon dioxide produced is removed by reaction with potassium hydroxide (Forming K 2 CO 3 + H 2 O as shown below), as oxygen is used by cellular respiration the volume of gas in the respirometer will decrease. As the volume of gas decreases, water will move into the pipet. This decrease of volume, as read from the scale printed on the pipet, will be measured as the rate of cellular respiration (Cell Respiration).

CO 2 + 2KOH —> K 2 CO 3 +H 2 O

The purpose of this lab was to measure the rate of cellular respiration. There are three ways to measure the rate of cellular respiration. These three ways are by measuring the consumption of oxygen gas, by measuring the production of carbon dioxide, or by measuring the release of energy during cellular respiration (Respiration). In order to measure the gases, the general gas law must be understood. The general gas law state: PV=nRT where P is the pressure of the gas, V is the volume of the gas, n is the number of molecules of gas, R is the gas constant, and T is the temperature of the gas (Respiration). The rate of respiration of germinating and non-germinating peas in this experiment was determined by the consumption of oxygen. Potassium Hydroxide (KOH) was used to alter the equilibrium. KOH removed the carbon dioxide and oxygen was used by cellular respiration thus decreasing the gas in the respirometer. The rate of respiration in germinating peas was compared to the rate of the non-geminating peas. These peas were placed in two different temperatures: 10ºC and 23ºC.

The hypothesis of this lab states that if the peas are germinated then the rate of cellular respiration will be higher in both room temperature and cold temperature. If the temperature of water is cooler than room temperature, then the process of cellular respiration of the peas will decline.

v  Room-Temperature Water Bath                      Nonabsorbent Cotton

v  Cold Water Bath                                             15% Potassium Hydroxide (KOH) Solution

v  Container of Ice                                              Dropping Pipets

v  Paper (White or Lined)                                   Forceps

v  Water                                                              Thermometers

v  Germinating Peas                                            Stopwatch (Timer or Clock)

v  Nongerminating Peas                                      Calculators (Optional)

v  Glass Beads                                                    Absorbent Cotton Balls

v  Respirometers                                                 Graduated Tube

Setup of Respirometers and Water Baths

There are two water baths (trays of water) to buffer the respirometers against temperature change and to provide two temperatures for testing: room temperature and a colder temperature (Approx. 10°C). Place of sheet of paper in the bottom of each water bath. This will make the graduated pipet easier to read. Next, place a thermometer in each tray. If necessary, add ice to the cold-temperature tray to further cool the water to get it as close to 10°C as possible. While waiting for the cold- water temperature to stabilize at 10°C, prepare the three respirometers to test at room temperature, and prepare an identical set of three respirometers to test at the colder temperature.

Prepare Peas and Glass Beads

Respirometer 1 : Put 25 mL of H 2 O in your 50-mL graduated plastic tube. Drop in 25 germinating peas. Determine the volume of water that is displaced (equivalent to the volume of peas). Record the volume of the 25 germinating peas. Remove these peas and place them on a paper towel.

Respirometer 2 : Refill the graduated tube to 25 mL with H 2 O. Drop 25 dry, nongerminating peas into the graduated cylinder. Next, add enough glass beads to equal the volume of the germinating peas. Remove the nongerminating peas and beads and place them on a paper towel.

Respirometer 3 : Refill the graduated tube to 25 mL with of H 2 O. Add enough glass beads to equal the volume of the germinating peas. Remove these beads and place them on a paper towel.

The independent variable is the type of peas (Germinated or Nongerminated) and the temperature (Room or Cold Temperature). The dependent variable is the consumption of oxygen from all 6 respirometers. The control group is respirometer three from both temperatures that consists of only glass beads.

Respirometer Assembly

This requires three respirometers for room-temperature testing and three respirometers for cold-temperature testing.

To assemble a respirometer, place an absorbent cotton ball in the bottom of each respirometer vial. Use a dropping pipet to saturate the cotton with 2 mL of 15% KOH. ( Caution : Avoid skin contact with KOH. Be certain that the respirometer vials are dry on the inside. Do not get KOH on the sides of the respirometer.) Place a small wad of dry, nonabsorbent cotton on top of the KOH- soaked absorbent cotton. The nonabsorbent cotton will prevent the KOH solution from contacting the peas. It is important that the amount of cotton and KOH solution be the same for each respirometer.

• Place 25 germinating peas in the respirometer vial(s) 1.
• Place 25 dry peas and beads in your respirometer vial(s) 2.
• Place beads only in your respirometer vial(s) 3.

Insert stopper fitted with a calibrated pipet into each respirometer vial. The stopper must fit tightly. If the respirometers leak during the experiment, you will have to start over.

Placement of Respirometers in Water Baths

Place a set of respirometers (1, 2, and 3) in each water bath with their pipet tips resting on lip of the tray. Wait five minutes before proceeding. This is to allow time for the respirometers to reach thermal equilibrium with the water. If any of the respirometers begins to fill with water, the experiment will have to restarted.

After the equilibrium period, immerse all respirometers (including pipet tips) in the water bath. Position the respirometers so that it’s easy to read the scales on the pipets. The paper should be under the pipets to make reading them easier. Do not put anything else into the water bath or take anything out until all readings have been completed.

Take Readings

Allow the respirometers to equilibrate for another five minutes. Then, observe the initial volume reading on the scale to the nearest 0.01 mL. Record the data in Table 1 for Time 0. Also, observe and record the temperature. Repeat your observations and record them every five minutes for 20 minutes.

(Cell Respiration)

Results/Data Collection

Table 1: Respiration of Peas at Room Temperature

*All values are in mL except °C and Time

Table 2: Respiration of Peas at 10° C

*All values are in mL °C and Time

Discussion/Conclusion

The results of this lab show that the germinating peas had consumed more oxygen at a faster rate than the non-germinating peas and the beads had. The non-germinating peas and the beads showed to consume barely any oxygen at all. In this lab, the germinating peas respiration rate proved to be faster than the respiration rate of non-germinating peas. Finally, this experiment showed that respiration rates increase as the temperature increases. Concluding that temperature and respiration rates are directly proportional and have a direct relationship to each other. From this experiment, it can also be concluded that the germinating peas that were undergoing the process of cellular respiration had a much higher oxygen consumption rate than the consumption rate in non-germinated peas and the glass beads. The non-germinating peas shows hardly any consumption of oxygen. Since the germinating peas are germinating or sprouting, they require a more extensive amount of energy or ATP. This allows them to have high oxygen consumption rates or respiration rates in this experiment. In addition to the germinating peas, the non-germinating peas, are not germinating so because of this they do not need significant amount of ATP production. Therefore, the non-germinating peas have a significantly low rate of respiration in comparison with the germinating peas. The rate at which they respire was most prevalent in the first respirometer since they were all germinating peas. The data table and graph accurately depict this idea or trend with the germinating and non-germinating peas.

Numerous errors could have occurred during the lab. Miscalculation of the glass beads which went into the respirometer, and hence would ruin the controlled results. The seals on the respirators may not have been completely air-tight which may have caused a leak and therefore oxygen would have been lost altering the data.  The temperature may have been slightly off in the water baths. There was also the problem of reading the scales on the pipets which could have lead to improper measurements of the water position.

To improve this experiment, more accurate and precise instruments can be used such as a advanced pipet which has scales that are easy to read. Also a completely air tight respirometer instead of using petroleum jelly which water can still leak in.

Literature Cited

Campbell, Neil A., and Jane B. Reece. Biology . Eighth Ed. San Francisco: Pearson Benjamin Cummings, 2008. Print.

Cell Respiration . AP Biology Laboratory 5: Carolina Biological Supply Co., 2005. Print.

“Respiration.” StudyMode.com . StudyMode.com, 06 2011. Web. 06 2011. http://www.studymode.com/essays/Respiration-713319.html

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Measurement of Respiration and Effect of Temperature

Learning Objectives

After completing the lab, the student will be able to:

• Measure the consumption of oxygen during respiration.
• Measure the effect of environmental conditions on respiration in pea seeds.

Activity 2: Pre-Assessment

• Students stain corn seeds over a period of several days after the seeds are soaked with water to promote germination with iodine. Iodine stains starch blue. The students observe that the amount of starch decreases during germination. Can you explain this observation? Which metabolic process uses up starch?
• What kind of biological catalysts are involved in the reactions of respiration? If the rate of a chemical reaction doubles with the temperature, would you expect that rates of respiration to increase continuously with temperature?
• Discuss the answers to questions 1 and 2 with the class.

Activity 2: Measurement of Respiration and Effect of Temperature on Respiration Rate

Imagine that you plan to monitor respiration in a whole organism, such as a small invertebrate or a seedling. You may decide to follow the disappearance of the reactants, either glucose or oxygen. Your second choice is to measure the formation of the products, either water or carbon dioxide. In this laboratory, you will design experiments to assess the effect of environmental conditions on the process of cellular respiration.

In respiration, oxygen is consumed and CO2 is released. In this experiment, we will measure the disappearance of oxygen. A respirometer consists of an enclosed chamber in which the studied organism is placed and a graduated pipette with which we measure changes in the gas volumes. The CO2 gas that forms will be removed by adding Ca(OH)2, which reacts with carbon dioxide to form the insoluble salt CaCO3, calcium carbonate.

While measuring the changes in the amount of gas produced, you will consider the ideal gas law equation which can be stated as

P represents the atmospheric pressure in mmHg, V is the volume of the gas in liters, n is the number of moles of gas, R is the ideal gas constant, and T is the temperature in degrees Kelvin. In the respirometer, pressure remains constant as the gas produced displaces water in the tube. We will set up the respirometers in a water bath to minimize fluctuations in temperature.

In this experiment, you will use pea seeds. In a seed, like the yellow peas shown in Figure 8.2, a tough coat protects the plant embryo. Nutrients in the form of starch and lipids surround the embryo and support its germination , or growth from seed, until the appearance of photosynthetic structures. Seeds are normally dormant , that is metabolically inactive, until the environmental conditions helpful for growth are available. In order to bring the seeds to an active state, (out of dormancy), the seeds you will use were soaked in water via a process called imbibition, for 6 to 8 days.

Cellular respiration involves three major sequential stages: glycolysis, the citric acid cycle, and oxidative phosphorylation. Oxygen serves as a terminal electron acceptor. Glycolysis takes place in the cytoplasm whereas mitochondria are the site of the citric acid cycle and the electron transport chain.

All the steps of respiration are mediated by enzymes , biological catalysts—mainly proteins—that lower the activation energy , the energy required to be available in a system before a chemical reaction can take place. Enzymes are not used up by the reactions they catalyzed. The process of respiration responds to the same environmental factors that affect the activity of enzymes. In this activity, you will measure the effect of temperature on respiration rates.

Safety Precautions

• Handle test tubes or glass containers with care; insert the plug by holding the container in a paper towel.
• Use plastic pipettes rather than glass pipettes.
• Wear goggles or safety glasses.
• Wear gloves when working with KOH or lime [Ca(OH) 2 ], which are corrosive chemical compounds.
• Use care while handling hot water. Wear mitts and do not leave boiling water or a hot plate unattended.
• Protect your clothes with an apron.
• Inform your teacher immediately of any broken glassware as it could cause injuries.
• Clean up any spilled fluids to prevent other people from slipping.
• Wash your hands with soap and water after completion of the activity.

For this activity, you will need the following:

• Dried yellow peas
• Glass beads
• Balance and weigh boats
• Paper towels to imbibe seeds
• KOH or lime water
• Food coloring
• Absorbent and non-absorbent cotton
• Drilled rubber stoppers that fit the opening of the test tubes or bottles
• 1-ml plastic pipettes
• Top loading balance
• Thermometers
• Water baths
• Weights such as clamps or hex keys
• Wide glass test tubes or bottles
• Stirring rod
• Hot plate to boil water

For this activity, you will work in pairs .

Structured Inquiry

Step 1: Obtain 25-30 germinating peas, dry peas, and glass beads to start your experiment. Place the germinating peas in a weigh boat and measure their weight. Record the weight in your notebook and then repeat for the dried peas and glass beads.

Step 2: In this activity, you will indirectly measure the rate of respiration of the peas by monitoring the decrease in gas when the peas are placed in the respirometer chamber. What gas will decrease in the chamber as the peas undergo respiration? Hypothesize how much the gas levels will likely change for the germinating seeds, dry seeds, and glass beads. Record your hypotheses and predictions in your notebook.

Step 3: Student-Led Planning: Which of your treatments serve as a control? Is this a positive or negative control? How will this control reveal whether or not the experiment is functioning properly? Write your answers in your notebook.

Step 4: Assemble a respirometer using Figure 8.3 as a guide and following the steps below.

• In a wide test tube (or bottle), drop a pad of absorbent cotton. Pack down the cotton with a stirring rod. Add lime water Ca(OH)2, being careful not to oversaturate the pad or drip the lime water on the side of the tube.
• Insert a thin layer of non-absorbent cotton, pushing down with the glass rod. The cotton protects the seeds from lime water; however, if it is too thick, it will interfere with the diffusion of CO2.
• Plug the test tube with a bored rubber stopper. Add a drop of colored water in a 1-ml graduated pipette and insert the pipette in the hole of the stopper. Adjust the position of the drop by inserting a syringe in the stopper until you can easily read the position of the dye. (The syringe is not shown in Figure 8.3.) Rub some petroleum jelly where the pipette comes into contact with the rubber stopper. The respirometer must be water tight to yield reliable results. It is also possible to wrap the openings with stretchable plastic film.
• You may want to test for leaks by immersing the respirometer with the plug and pipette before filling it with reagents and cotton.

Step 5: Assemble the respirometer containing the control sample in the same manner.

Step 6: Immerse the respirometers with the experimental sample and the control in the water bath. Lining the water bath with a white paper towel will make it easier to read the markings on the pipettes. Make sure that the pipettes are resting across a piece of ribbon or string that spans the width of the water bath, as illustrated in Figure 8.4. The goal is to keep the pipettes out of the water while the test tubes remain submerged.

Step 7: Let the respirometers equilibrate for 5–10 minutes.

Step 8: Read the starting volume on the pipette. This is time 0 min. Record the displacement of the colored bead for all samples every 2 minutes for 20 minutes and enter data in a table of measurements.

Step 9: Critical Analysis: Calculate the changes in volume where the reading at time 0 is subtracted from every subsequent reading. Subtract the rate of volume change measured in the control samples to obtain a corrected rate of respiration.

Graph the changes in volume in respirometers as a function of time and calculate the rate of change from the slopes of the line plots. Calculate the rate of change per gram of seed. This will allow you to compare values obtained from different samples. Draw a plot of changes in gas volumes from the data in your table. What measurements will you enter on the axis? What measurements will you enter in the y -axis? Determine the rate of respiration in your experiment. How did you use the data from your control or controls? Did volumes change during the experiment? Which gas caused the change in volume? Do the results support your hypothesis? Can you explain unexpected results? Were the respirometers water-tight at all times? How could you modify the experiment in the future? Write your answers in your notebook.

Guided Inquiry

Step 1: Repeat the steps to set up the respirometers described in the Activity 2 Structured Inquiry. Use three water baths at the following temperatures: 10°C, room temperature (see Structured Inquiry), and 50°C.

Step 2: Hypothesize/Predict: Discuss with your partner what kind of influence temperature might have on metabolic processes. How would the respiration rate measured at 10°C compare to the rate measured at room temperature? Will the rate of respiration be higher at 30°C than room temperature? Do you predict that the rate of respiration will be higher at 50°C than at room temperature or 30°C? Enter your hypotheses in your notebook.

Step 3: Student-Led Planning: You will now measure the rate of respiration at three different temperatures. Discuss with your partner if you need to run the experiment at room temperature again. Decide which control you will set up for this experiment. Make a note of all the steps you will perform, as you did in Activity 2, and create tables for your observations in your lab notebook. You will take readings of the colored water bubble at 2-minute intervals for 20 minutes. Have your teacher approve your experimental procedure before proceeding.

Step 4: Once approved, carry out your experimental procedure, closely monitoring the temperature as you take measurements.

Step 5: Critical Analysis: Graph the changes in gas volumes from the data in your table for all three temperatures for the experimental and control set-up, as you did for the Structured Inquiry. Determine the rate of respiration for each temperature. Because the gas law shows that differences in temperature affect volumes, you must correct for any changes in volume that are a consequence of temperature variations rather than respiration. To do this, subtract changes in volumes measured in the respirometer containing glass beads from the changes in volume measured in the tubes containing germinating seeds held at the same temperature. Do the results support your hypothesis? Explain whether your results support or refute your hypothesis. How could you modify the experiment in the future? Write your ideas in your notebook.

Assessments

• Students record changes in gas released from respirometers containing germinating seeds and dry seeds. They set up their tubes in air rather than in a water bath. A thermometer probe is inserted in each respirometer. The tube that contains germinating seeds shows an increase in temperature. No such increase is recorded in a respirometer that contains dry seeds. What is the reason for the difference in temperature?
• The ideal gas law shows that volume depends on temperature as well as pressure. Why do you set your respirometers in a water bath?
• A classmate insists that there are no mitochondria in leaves because chloroplasts produce ATP through photosynthesis. How would you experimentally disprove this claim?

Lab Manual for Biology Part I Copyright © 2022 by LOUIS: The Louisiana Library Network is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License , except where otherwise noted.

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Investigation - What Factors Affect Cellular Respiration? 

This investigation uses respirometry techniques to calculate the rate of oxygen consumption (cellular respiration) in germinating pea seeds.   The effect of temperature and whether a seed has broken dormancy are quantified and graphed.  The ideal gas law and its concepts are reviewed and applied.

Basic Questions (scientific practices)

• What is the relationship between temperature, volume, and pressure?
• How can repiration rates be measured using a respirometer?

Experimental Questions:

• How is respiration rate affected by temperature?
• How does the respiration rate of a germinating see differ from that of a dormant seed?
• Understand the relationships between temperature, pressure and volume.

Each individual cell is responsible for the energy exchanges necessary to sustain its ordered structure.  Cells accomplish this task by breaking down nutrient molecules to generate ATP (adenosine triphosphate), which can then be used to run cellular processes that require energy.  This process is called cellular respiration which requires nutrient molecules and oxygen.   Carbon dioxide and water are products of the series of reactions involved in cellular respiration.

There are several methods of indirectly measuring the rate of cellular respiration in organisms.  One method involves monitoring changes in temperature; since the process of respiration is exergonic (produces heat).  Another method is to measure either the oxygen consumption or the carbon dioxide production.  Respirometers are devices that measure these types of gas volume changes, and therefore provide information about the rate of cellular respiration.

In order to be able to use a respirometer, you will need to use the ideal gas law , which describes the relationship between temperature, pressure and volume. (PV = nrT)

During cellular respiration, two gases are changing in volume.  Oxygen gas is being consumed by the respiring cells and carbon dioxide gas is diffusing out of the cells.  The respirometer, therefore, has to be able to deal with two simultaneously changing gas volumes.  This is accomplished by introducing potassium hydroxide into the device.  KOH absorbs carbon dioxide, following this equation

CO 2 + 2KOH --> K 2 CO 3 + H 2 O

Potassium carbonate ( K 2 CO 3 ) is a solid precipitate.  Any CO 2 produced is immediately converted from a gas to a solid and is therefore no longer governed by gas laws.  This allows the respirometer to measure only one variable, the consumption of oxygen gas by living cells.

Assembling the Respirometers

Two sets of respirometers will be assembled during this lab exercise. Each set will be incubated at a different temperature. One respirometer will contain germinating seeds, one will contain a mix of nongerminating seeds and plastic beads with a volume equal to the first vial.   Respirometers will be submerged in a pan of either cold or room temperature water and the rate of respiration will be measured by observing the movement of water into the pipet.

Lab Materials :  Germinating pea seeds, dry  pea seeds, plastic beads, 2 respirometers, absorbent cotton, nonabsorbent cotton, 1 round wood stick,   water bath, ice, 100 ml graduated cylinder, stopwatch or clock, water. Dropper Bottle of 15% KOH

Safety: Wear safety goggles. KOH is caustic, avoid direct skin contact.

1. Fill a graduated cylinder with 20 ml of water. Place 20 germinating seeds in the cylinder and record the volume by reading the new level of water. Remove seeds and place on a paper towel.

Volume  of germinating seeds: ______

2. Fill the graduated cylinder with 20ml of water. Place 20 non germinating seeds in the water. Drop plastic beads into the cylinder until the volume is the same as the germinating seeds from step 1.

3. Obtain the glass respirometer vials. Place an absorbent cottonin the bottom and add KOH to saturate the  cotton. It should be soaked, but not dripping. Caution: KOH will burn the skin!

4. Place nonabsorbent cotton over the KOH soaked absorbant cotton to act as a barrier so your samples do not come into contact with the caustic substance.

5. Add the peas, peas/beads, and beads to the appropriate respirometer. Place the stoppers on each of the vials and ensure they are secured tightly. You will be assigned a temperature to measure the respiration rates (cold or room temperature.

*You may be asked to stop here and take readings tomorrow.*

6. Create your water bath with your  assigned temperature. Lean your respirometers on the edge of the bath so that  the temperature inside the chamber equals the temperature of the bath. Do no submerge them yet! Let them equalize  for  about 5 minutes.

7. If your water bath is in a dark plastic bin, place white paper towels at the bottom to make it easier to read the pipet.

8. Submerge your respirometers, a little bit of water will enter the tips at first. You may need to rotate the pipet in order to take readings, but once you have them submerged and situated, limit movement as this will affect your results.

11. Note: Read the pipet as the water bubble moves down the tube toward the respirometers. You are using a 1 ml pipet, so each of the units on the reading are .9, .8, .7, etc. The reading shown on the above image would be .74

*If you are having trouble finding the bubble, place a drop of food coloring in the water near the tip of the pipet.

Data and Analysis

Graph: Graph your data below. There will be 4 lines on this graph; label and color code. Draw a LINE OF  BEST  FIT.

Calculate Slope

The slope of your lines will represent the respiration rate of each of your  samples:

Respiration Rates for each sample:

1.   State a hypothesis that relates to temperature that is being tested by this lab exercise.

2.   State a hypothesis that relates to the state of seed germination that is being tested by this lab exercise.

3.    In this lab exercise, what is the purpose of the ….

a) Bead b) KOH c) Respirometer  

4. Explan why it was important that the vials contained the same volume. Use the Ideal Gas Law in your explanation.

5. The instructor that created this lab did not have you make a control, though many other similar labs require students to assemble a third respirometer as a control.  Review how you designed your tests and suggest what your control respirometer would look like.  It will not just be an empty vial.

6. Write a summary for this experiment where you make a CLAIM that answers the experimental question, then provide EVIDENCE to support that claim.  Finally, use scientific REASONING to explain the results.

Resources on Cell Respiration

See Investigation: What Factors Effect Cellular Respiration?

Cell Respiration Extension Questions

Cellular Respiration Graphic Organizer

Rate of Respiration Virtual Lab  – use a simulator to show change in respiration of germinating seeds

Case Study:  The Cyanide Murders  –  explores cellular respiration and why we need oxygen

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Cellular Respiration in Germinating Peas Lab Data Sheet

Plant physiology (hort 6430e), university of georgia.

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Cellular Respiration in Germinating Peas Claire Murad 4/14/

I. Introduction The objective of this lab is to conduct an experiment that shows the three stages of cellular respiration (Glycolysis, acetyl-CoA synthesis/Krebs cycle, and Electron- Transport Chain) are incorporated into the results. The purpose of this lab is to emphasize the roles oxygen and carbon dioxide have in the process of cellular respiration while using a respirometer to measure the rate of respiration in the germinated peas and dormant peas. This process must be done correctly, or the results will not be accurate, such as water seeping into the vial. The statement would mean the volume change would be messed up as there should be a seal between the pipet and vial. II. Results In Activity 1, the germinated peas (25 peas), dormant peas + beads (25 dormant peas), and beads, all had the same final volume, initial volume, and total volume. There were 35 beads counted in the volume of the beads to achieve the same initial volume, final volume, and total volume as the other two samples. The different numbers of beads were to help results show the same volumes across the board. For the dormant peas + beads, there were 31 beads counted to accomplish the same volumes. In Activity 2, Respirometer 1 (germinated peas) had a consistent decrease in volume change in the 20 minutes, Respirometer 2 (dormant peas + beads) had a consistent decrease until it reached a plateau at 15 minutes, and Respirometer 3 (beads) showed no change in volume throughout the 20 minutes. Data Data Table 1 (Activity 1) Sample Initial volume (Vi ) (mL) Final volume (VF) (mL) Total volume (VF–Vi ) (mL) Germinating peas 25 mL 34 mL 9 mL Dormant peas + beads 25 mL 34 mL 9 mL Beads only 25 mL 34 mL 9 mL

Data Table 2 (Activity 2) Water temp. (°C) Time (min) Resp. # Volume in pipet Resp. # Change in volume Resp. # Correcte d volume change Resp. # Volume in pipet Resp. # Change in volume Resp. # Correcte d volume change Resp. # Volume in pipet Resp. # Change in volume 20 0 0 0 0 0 0 0 0 0 20 5 0 0 0 0 0 0 0 0 20 10 0 0 0 0 0 0 0 0 20 15 0 0 0 0 0 0 0 0 20 20 0 0 0 0 0 0 0 0 Figure 4 This figure shows the setup of Activity 2 experiments and the rate of respiration. This figure was for the settling of the vials (5 minutes) before conducting 20 minutes of the rate of respiration. The germinated peas in one respirometer, dormant peas

• beads in another and beads in the last respirometer.

Figure 5 This figure shows the results after 20 minutes of submerging the respirometers to observe the change of volume for the rate of respiration. The germinated peas with the most volume change in the pipet, the dormant peas have little volume change, and the beads with no change in the pipet.

• The respirometer that serves as the control is Respirometer #3, the beads are not living, and it was consistent with showing no results, meaning there was no decrease in the volume of gas. This makes Respirometer #3 the one to be the control as there is a comparison to be made between all respirometers.
• The germination of peas is one of the variables that changed to bring about the observed change in volume. The peas, when fully germinated, can produce more change in comparison to the beads and non-germinated peas.
• Respirometer 1 had the highest change in volume compared to Respirometer 2. The difference is caused by the prior treatment that the peas had before experimenting. The germinated peas were submerged in water and a damp towel for 48 hours, on the other hand, the dormant peas had no treatment. The dormant peas did not have as much oxygen as the germinated peas, causing the difference in volume to change.
• Multiple Choice

Course : Plant Physiology (HORT 6430E)

University : university of georgia, this is a preview.

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BIOLOGY JUNCTION

Test And Quizzes for Biology, Pre-AP, Or AP Biology For Teachers And Students

Lab 5 Cellular Respiration by Kris Layher